Amalgamator



Nov. 18, 19 41. E. A. WILLNER, SR 2,263,325

AMALGAMATOR Patented Nov. 18, 1941 AMALGAMATOR Ernest Alfred Willner, Sn, Denver, 0010.

Original application March 21, 1936, Serial No.

70,068. Divided and this application April 8, 1939, Serial No. 266,869

1 Claim.

The present application is a division of my copending application for Placer gold concentrator and amalgamator, Ser. No. 70,068, filed March 21, 1936.

The invention herein set forth relates to amalgamators, and more particularly to an amalgamator which is incorporated in the mechanism of the parent application, the mechanism being designed to operate on crude ore to first separate the concentrates out of the ore and then to separate the gold out of the concentrates, with special reference to the finely divided or flour gold occurring in the ore.

The primary object of the invention is the provision of an amalgamator which will break the surface tension of the flour gold while agitating the concentrate in the presence of mercury.

Another object is the provision of a device and of a method especially applicable for refining placer gold ores in which the gold occurs in the form of extremely minute particles known as flour gold.

Another of my objects is the provision of a specialized form of centrifugal bowl for breaking up the surface tension of the film surrounding the particles of flour gold so that the gold may come into amalgamating contact with the mercury in the bowl.

Another object is the provision of means for causing movement of the concentrate over amercury surface under pressure of the concentrate and for agitating the concentrate in the presence of the mercury.

Another object is the provision of a centrifugal bowl with inner peripheral grooves for retaining mercury combined with means for conducting a thin layer of the concentrate under agitation over the mercury and other means for discharging thin streams of water under pressure against the thin layer of concentrate to reinforce the centrifugal pressure of the concentrate against the mercury.

Having in view these objects and others which will be pointed out in the following description, I will now refer to the drawing in which Figure l is a median vertical sectional View of the amalgamator.

Figure 2 is a top plan View of the amalgamator, a portion being shown as it appears with the screen and apron and water conduits removed therefrom.

The preliminary treatment of the crude ore and the apparatus employed in that treatment are fully described in the parent application of which this is a division. In brief, the crude ore is treated to separate the concentrate from the portion of the crude ore which is to be rejected because of too little or no gold content. The concentrate with its load of finely divided flour gold is'discharged into the amalgamator 4|. This amalgamator consists of a centrifugal bowl of highly specialized form. As shown in Figures 1 and 2, the bowl itself is frusto-conical in shape with its sides inclined upwardly and outwardly. The walls of the bowl forming the sides of the frustrated cone as shown in Figure 1 are inclined onlya few degrees from the vertical thereby making the frusto-conical bowl nearly cylindrical. This substantially vertical disposition of the walls permits the attainment of a maximum pres-- sure due to centrifugal force without imp n the upward movement of the ore concentrate over the mercury to any appreciable degree. The bowl is secured to a shaft 42 and it is provided with a large annular groove in its floor, the groove surrounding its axis as shown in Figure 1. The inner sides are provided with circular grooves of the form shown in Figure 1. These grooves have substantially horizontal upper walls which are then inclined in the direction of the walls of the bowl and which terminate in lower walls sloping downwardly and towards the axis of the bowl. The inner grooves in the walls of the bowl are designed for the reception of the mercury against which the ore particles are to be driven. Since the surface tension of the film about the particles of flour gold is enormous as compared with the surface tensionvof larger particles of gold, it is necessary to employ every possible device for breaking up this surface tension in order to permit the fine particles of gold to come 7 into contact with the mercury. This is done by rotating the bowl 4| at a very high speed to provide the necessary centrifugal pressure which is accentuated by fine but powerful streams of water directed against the grooves in the sides of the bowl. This water enters through water pipes 43 which are connected with the water line 24.- It should be noted that the apertures in the pipes 43 are in every case directly opposite the grooves in the bowl so that the full force of the streams may be directed against the ore mass over the grooves to not only force the gold particles into contact with the mercury but also to keep the ore mass slightly agitated to prevent the gold particles from adhering to the larger ore particles and thus passing out of the bowl.

Owing to the peculiar problems involved the structure is still further modified. A stationary apron 44 extends downwardly parallel to the wall of the bowl. This is done to prevent the splashing of the water within the bowl. The larger particles of the ore as well as the finer particles containing no gold ore pass upwardly within the inner walls of the bowl to be discharged above the upper edge of the bowl. The bowl is therefore provided with a jacket 45 having a discharge chute 46 for receiving the discarded portions of the ore. Inside the bowl there is also a screen 41. A spout delivers the ore into the screen 41 from which the slushy ore drops to the bottom of the bowl 4 I It is very seldom that ore particles falling through the spout are large enough to cause trouble in the bowl 4| but such particles are readily removed by hand from the screen 41. The slushy ore falls toward the bottom and it is not permitted to move horizontally due to the stationary apron 44. As it approaches the bottom of the bowl 4| it encounters the disturbance of the impeller 48 having radially extending blades which not only agitates the ore mixture but which forces it past the bottom of the apron 44 and into its upward passage along the wall of the bowl 4|.

The shape of the grooves in the walls of the bowl 4| should be noted. In starting the amalgamator the mercury is first introduced and the bowl is then rotated. The movement of the mercury will be upward along the outer walls of the bowl 4|. It will fiow into the lowermost groove and then overflow from that groove into the next higher groove. This will continue until all the grooves are filled with mercury. When stopping the machine to remove the gold amalgam, the mercury with the gold content will all flow to the bottom. of the amalgamator where it may be removed by first releasing the plug 49 to drain out the gold amalgam.

The flour gold in the concentrate is thus absorbed by the mercury in the grooves of the amalgamator. The fine sand and water are slushed over the sides of the amalgamator and they flow down into and through the chute 46. In passing through the chute 46 the sand and water'is in condition of violent agitation due partly to the inflow of the concentrate from the conduit 38 and partly to the rapid rotary movement of'the amalgamator 4|. The Volume of the amalgam in the grooves of the concentrator gradually increases due to the absorption of the flour gold by the mercury.

Flour gold occurs in many parts of the world but usually in streams. The form of the gold is very pure and it occurs in such immense quantities that it has for many years baflied metallurgists and others who have tried to devise methods for its recovery. Although occurring in such quantities, the flour gold is found in sand in all degrees of fineness which must be separated from the gold and discarded. This in itself is a. dimcult problem but the problem is made much more difiicult by the character of the flour gold itself. The particles are so extremely fine that they tend to remain suspended in flowing water which would carry the sand. Because of the large surface of the particles as compared with their volume and weight, the surface tension has resulted in a problem which has heretofore been insoluble.

The concentrates are fed through the amalgamator which is especially designed for extracting fiour gold from the concentrate. In this respect it diifers materially from those amalgamators which were designed for separating particles of gold of appreciable size from an ore mass. Owing to the light weight of the particles of flour gold as compared with the weight of the gold particles found in other ores, and due to the enormous surface tension about the fine particles of fiour gold, it is necessary to employ a construction which is quite different from that usually employed in amalgamators. The surface tension of the particles must be more than counter-balanced by the centrifugal pressure and I therefore employ a high speed centrifugal bowl and I reenforce the centrifugal pressure by means of streams of high velocity directed against the ore mass at its amalgamating points.

Having thus described my invention in such full, clear, and exact terms that its construction and operation will be readily understood by others skilled in the art to which it pertains, what I claim as new and desire to secure by Letters Patent of the United States is:

A centrifugal amalgamator comprising a frusto-conical bowl having a vertical axis, a plurality of horizontally positioned grooves in said bowl, a stationary annular apron spaced from the sloping wall of said bowl and co-axial therewith, means for conducting water positioned between said apron and said grooves, said means having openings directly opposite each of said grooves in the bowl, and an impeller composed of radially extending blades rotating with said bowl and mounted above the bottom of the bowl and below the end of the apron.

ERNEST ALFRED WILLNER, SR. 

